The long-term objective of this proposal is to establish a commercially viable program of illness self- management in people with unexplained chronic fatigue (UCF) and chronic fatigue syndrome (CFS). A successful self-management product has the potential (1) to improve the generally poor outcomes for UCF and CFS patients, (2) to greatly expand the availability of behavioral health care for UCF and CFS, and (3) to reduce medical and behavioral utilization for these patients. Evaluation of self-management strategies that that improve quality of life is a major goal of NINR, a sponsor of the program announcement for this proposal. This Phase II study is a randomized trial of a feasibility-tested fatigue self-management program that compares three conditions: (a) the Phase I self-management product utilizing web diaries and actigraphs (FSM: ACT); (b) the Phase I self-management product utilizing inexpensive paper forms and step counters (FSM: CTR) as would be done in Phase III commercialization; and (c) a wait list control condition. It is hypothesized that: (1) The FSM: ACT condition will be more efficacious than the wait list condition in lessening fatigue, improving functioning, and reducing depression. (2) The FSM: CTR condition will be more efficacious than the wait list control condition in lessening fatigue, improving functioning, and reducing depression. (3) Outcomes will not be significantly different between the FSM: ACT and FSM: CTR conditions. (4) The combined FSM conditions will be more cost effective than the wait list control condition. Our secondary aim will examine baseline behavioral outcome predictors including coping style, self-efficacy beliefs, and focusing on bodily symptoms. Phase III Commercialization. The self-management product will be promoted to (a) health plan decision makers (e.g., managed care companies and large employers),and (b) retail end users via targeted internet sites that offer products and support services to UCF/CFS patients. Commercial applications are potentially very broad given (1) the large population of individuals with UCF and CFS, (2) the high cost of (ineffective) medical care for these patients; (3) the unavailability of providers who administer behavioral treatment, and (4) the absence of a generally accepted self-management program for this patient population. A home-based commercially available illness management program for chronic fatigue is important because it potentially offers: (1) improved access to treatment for patients who may be unable or unwilling to travel to regular appointments; (2) a minimal time commitment and lower cost for higher credibility 'self- management' in comparison to face-to-face counseling and longer-term mental health care; and (3) a substantially reduced illness burden and improved quality of life for these debilitated patients.